UIC Leaflet 593: Standard for Intermodal Loading Units in Combined Transport

What is UIC Leaflet 593?

UIC Leaflet 593 is a fundamental document for Combined Transport, titled “Intermodal loading units (other than containers) for transport on wagons – Technical conditions for use.” While standard ISO containers are governed by global maritime rules, Swap Bodies and Semi-trailers require specific rail-centric standards to ensure they fit within the Loading Gauge and can be safely handled by railway cranes and reach stackers.

The leaflet ensures Interoperability by standardizing the points of contact between the road unit and the rail wagon. This allows a semi-trailer from a Turkish carrier to be safely loaded onto a German Pocket Wagon using standardized vertical lifting or horizontal loading techniques.

Technical Requirements for Loading Units

UIC 593 specifies the “Rail-ability” of road units. For a semi-trailer or swap body to be accepted for rail transport, it must meet several Technical Delivery Conditions:

• Grapple Arm Recesses: Road units must have reinforced “pockets” at the base where the crane’s grapple arms can securely grip the unit without crushing the side walls.
• Structural Integrity: The unit must be strong enough to withstand the vertical accelerations of rail travel and the longitudinal forces (shunting shocks) without deforming.
• Folding Landing Gear: Semi-trailers must have landing gear that can be safely stowed to avoid interference with the wagon’s frame.

The Coding System (P-Code)

A vital component of UIC 593 is the Coding Systems used to prevent collisions with infrastructure. Every unit is assigned a “Profile Code” (e.g., P400).

• Dimensions: The code reflects the height and width of the unit when loaded on a specific wagon type.
• Route Verification: Infrastructure Managers use these codes to determine if a specific Combined Transport train can pass through certain tunnels or under bridges.
• Data Exchange: These codes are integrated into TAF TSI digital messages to automate train formation and route clearance.

Operational Safety and Securing

The leaflet also defines how units must be secured to the wagon. For swap bodies, this usually involves standardized “twist-locks” (similar to containers), while for semi-trailers, it involves securing the kingpin into a specialized “hitch” on the pocket wagon.

Comparison: ISO Containers vs. UIC 593 Units